From BiblePortal Wikipedia

Webster's Dictionary [1]

(1): (n.) That doctrine which, professing ignorance, neither asserts nor denies.

(2): (n.) The doctrine that the existence of a personal Deity, an unseen world, etc., can be neither proved nor disproved, because of the necessary limits of the human mind (as sometimes charged upon Hamilton and Mansel), or because of the insufficiency of the evidence furnished by physical and physical data, to warrant a positive conclusion (as taught by the school of Herbert Spencer); - opposed alike dogmatic skepticism and to dogmatic theism.

The Nuttall Encyclopedia [2]

The doctrine which disclaims all knowledge of the supersensuous, or denies that we know or can know the absolute, the infinite, or God.